1. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 1 GLAST Large Area Telescope: Introduction & Science Overview Peter F. Michelson Stanford University LAT Principal Investigator & Spokesperson peterm@stanford.edu (650) 723-3004 Gamma-ray Large Area Space Telescope

2. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 2 Introduction and Science Overview Outline  GLAST Mission and Science Overview  Large Area Telescope  instrument overview  transition from design to flight hardware fabrication  status: schedule, cost, international commitments  challenges

3. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 3 Through most of history, the cosmos has been viewed as eternally tranquil

4. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 4 ` During the 20 th century the quest to broaden our view of the universe has shown us the vastness of the Universe and revealed violent cosmic phenomena and mysteries

5. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 5 GLAST is an important part of the continuing quest to broaden our view of the universe.  observe, with unprecedented detail, cosmic arenas of extreme violence  explore Nature’s highest energy processes (10 keV – 300 GeV) - LAT: - LAT: ~20 MeV - >300 GeV - GBM: - GBM: correlative transient observations ~10 keV – 20 MeV

6. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 6 EGRET all-sky survey (70 MeV – 10 GeV)

7. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 7 3 rd EGRET Catalog AGN - blazars unidentified pulsars LMC

8. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 8 3 rd EGRET Catalog GLAST Survey: ~300 sources (2 days) GLAST Survey: ~10,000 sources (2 years)

9. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 9 GLAST Observatory Launch VehicleDelta II – 2920-10H Launch LocationKennedy Space Center Orbit Altitude575 Km Orbit Inclination28.5 degrees Orbit Period95 Minutes Orientation+X to the Sun Launch DateSeptember 2006 Large Area Telescope (LAT) Gamma Ray Burst Monitor (GBM) Spacecraft Person

10. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 10 GLAST Observatory Launch VehicleDelta II – 2920-10H Launch LocationKennedy Space Center Orbit Altitude575 Km Orbit Inclination28.5 degrees Orbit Period95 Minutes Orientation+X to the Sun Launch DateSeptember 2006 Large Area Telescope (LAT) Gamma Ray Burst Monitor (GBM) Spacecraft Person  e+e+ e-e- Si Tracker pitch = 228  m 8.8 10 5 channels 18 planes (16 with converters) Grid mechanical backbone LAT: 4 x 4 modular array 3000 kg, 650 W 20 MeV – 300 GeV Data Acquisition CsI Calorimeter hodoscopic array (8 layers) 6.1 10 3 channels ACD segmented scintillator tiles

11. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 11 GLAST - LAT measures gamma-rays in the energy range ~20 MeV - >300 GeV - GBM provides correlative observations of transient events in the energy range ~20 keV – 20 MeV GLAST measures the direction, energy & arrival time of celestial gamma rays  e+e+ e-e- Point Source Sensitivity: < 6 x 10 -9 ph cm -2 s -1 (est. performance: < 3 x 10 -9 ph cm -2 s -1 ) Source Localization: 0.3’ – 1’ Single Photon Angular Resolution 3.5 o @ 100 MeV 0.15 o @ 10 GeV Large Effective Area (A eff ) peak > 8,000 cm 2 Wide Field of View (> 2 sr) Good Energy Resolution  E/E ~ 10%; 100 MeV – 10 GeV ~ < 20%; 10 GeV – 300 GeV Low dead time: < 100  s/event Wide Energy Range: 20 MeV - >300 GeV 40 times EGRET’s sensitivity and extends energy range to 300 GeV

12. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 12 Transition from design to flight hardware fabrication Engineering Models constructed for each hardware subsystem – under test and evaluation have carried out subsystem Peer Design Reviews of each subsystem; Jan - March 2003 Production readiness reviews long-lead parts ordered and long-lead fabrication initiated finalizing flight instrument design details: comprehensive review at LAT Critical Design Review (CDR) – CD-3; May 12-16, 2003

13. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 13 LAT Schedule highlights GLAST scheduled for launch in September 2006 FABRICATION PHASECOMMISSIONING PHASE Build & Test Flight Units Observatory I&T Final Design Engr’g Models LAT I&TPrelim. & Sys. Design Ops. Begin LAT I&T Critical Design Review PDR Balloon Flight TKR & CAL FM A/B Schedule Float Launch Scheduled LAT Delivery Scheduled Completion Calendar Years 20002001200220032004200520062011

14. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 14 Summary Schedule FABRICATION PHASE COMMISSIONING PHASE LAT Complete 5/25/05 9/22/05 9/06 { Electronics Fab & Test Tracker Fab & Test Calorimeter Fab & Test ACD Fab & Test GRID Fab & Test Instrument I&T Beam Test Ship Instrument Observatory I&T Launch LAT Operations & Data Analysis  3 wks Schedule Float } Begin assembly 6/15/04 14 wks Schedule Float recently moved beam test to after completion of instrument I&T preserves LAT completion date adds schedule float between subsystem deliveries and I&T need dates

15. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 15 Budgeted Fabrication Cost Budgeted DOE + NASA Costs for Fabrication Phase (escalated $M) Baseline3/31/03 Budgeted Cost at Completion100.0107.5 Contingency 21.2 14.2 Total Estimated Cost (TPC=TEC)121.2121.7 Baseline 3/31/03 Budgeted costs at risk 72.7 59.4 Contingency fraction 29% 24%

16. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 16 LAT Hardware: International Contributions e+e+ e–e–  Si Tracker Grid (& Thermal Radiators) CsI Calorimeter ACD Electronics, Data Acquisition & Flight Software

17. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 17 Status of International Contributions Since baseline, international partners have delivered on commitments –Italy: (ASI/INFN) tracker –Japan: tracker (Si-strip detectors) –Sweden: calorimeter (CsI xtals) –France: calorimeter (CDEs, mechanical structure) On Thursday, April 24, CNES (the French Space Agency) announced their withdrawal from planned commitments to the French contributions to GLAST –impacting critical procurements by our partners at CEA and IN2P3 –we are working with CEA, IN2P3, and NASA and DOE, to understand the available options for maximizing the continued French contributions –in the short term (next few weeks), our French partners at CEA and IN2P3 will continue working; we are beginning implementation of backup plans for production in the U.S. of calorimeter flight components (.e.g. CDEs). –by the end of May, a revised plan will be presented to the collaboration sponsors

18. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 18 status summary and highlights of next year International Finance Committee formed to regularly review funding agency commitments – 1 st meeting, February 18-19, 2003 the transition from design to flight fabrication is currently underway first flight hardware deliveries to SLAC scheduled for February- March, 2004 –first 4 calorimeter and tracker flight modules will arrive at SLAC –LAT Grid delivered June 2004 – LAT integration begins collaboration meeting planned for Sept 15-19, 2003 in Rome, Italy –meeting will concentrate on collaboration plan for operations phase: instrument operations, science data analysis, etc.

19. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 19 Challenges loss of CNES support for French contributions –schedule impacts being mitigated now by application of contingency; –by end of May, will have revised CAL manufacture plan for presentation to DOE/NASA JOG, including CEA and IN2P3 contributions that can be confirmed very demanding schedule –subsystem development delays compensated by rescheduling beam test identification and closure of remaining design issues –issues identified (e.g. peer reviews, etc.); plans exist to close open issues

20. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 1 Introduction & Science Overview 20 ` GLAST: Exploring Nature’s Highest Energy Processes September 2006 launch